This invention relates generally to the field of transmitting and processing telecommunication data, and particularly to a system and method to effectively suppress idle fax signals.
During a transmission of a fax, there may be idle time periods where only idle signals are transmitted. To make the fax transmission more efficient, these idle signals should be suppressed and not sent to the receiving telecommunication device. Furthermore, care must be taken to avoid accidental suppression of valid fax data.
Accordingly, a system and method to effectively suppress idle fax signals without affecting transmission of valid fax data is desired.
The present invention provides a system and method to effectively suppress idle fax signals.
In accordance with one embodiment of the present invention, short term energy levels of a fax indicator signal and fax data following the fax indicator signal are computed. The short term energy of the fax data is compared to the short term energy of the fax indicator signal. If the short term energy of the fax data exceeds the short term energy of the fax indicator signal by a predetermined energy level value, the fax data is presumed to be valid fax data and is transmitted. If the short term energy of the fax data fails to exceed the short term energy of the fax indicator signal by a predetermined energy level continuously for a selected period of time or a hang over time, the fax data is presumed to be void or invalid fax data and is discarded. Since only valid fax data is transmitted, the amount of bandwidth required to transmit the fax data is generally reduced.
In one embodiment, the method includes detecting a fax indicator signal. The method further includes calculating a short term energy of the fax indicator signal. The method also includes calculating a short term energy of fax data subsequent to the fax indicator signal. In addition, the method includes discarding the fax data when the short term energy of the fax data fails to exceed the short term energy of the fax indicator signal.